Why can't Remote Assistance Connection be established?

When user tried to establish a Remote Assistance session, error messages appear and the session cannot be started

Err Msg: On host sideYou have been disconnected from client computer. For more information, contact client.

Err Msg: On client sideYou have been disconnected from host computer. For more information, contact host.

Microsoft has confirmed this symptom.To resolve this symptom, please download and install the file from the Microsoft Download Center: http://www.microsoft.com/downloads/release.asp?ReleaseID=33873&area=search&ordinal=1

For more information, please refer to the following solution in Microsoft's technical support website.Final Update : 2001/11/16Title: Cannot Establish a Remote Assistance ConnectionURL: http://support.microsoft.com/support/kb/articles/q311/8/89.asp